TY - JOUR
T1 - Preventing the calorie restriction-induced increase in insulin-stimulated Akt2 phosphorylation eliminates calorie restriction's effect on glucose uptake in skeletal muscle
AU - Sharma, Naveen
AU - Arias, Edward B.
AU - Sequea, Donel A.
AU - Cartee, Gregory D.
N1 - Funding Information:
This research was supported by the National Institute on Aging grants AG-010026 and AG-013283 . Naveen Sharma and Edward Arias contributed equally to this study.
PY - 2012/11
Y1 - 2012/11
N2 - Calorie restriction (CR; ~60% of ad libitum, AL, consumption) improves insulin-stimulated glucose uptake in skeletal muscle. The precise cellular mechanism for this healthful outcome is unknown, but it is accompanied by enhanced insulin-stimulated activation of Akt. Previous research using Akt2-null mice demonstrated that Akt2 is essential for the full CR-effect on insulin-stimulated glucose uptake by muscle. However, because Akt2-null mice were completely deficient in Akt2 in every cell throughout life, it would be valuable to assess the efficacy of transient, muscle-specific Akt inhibition for attenuation of CR-effects on glucose uptake. Accordingly, we used a selective Akt inhibitor (MK-2206) to eliminate the CR-induced elevation in insulin-stimulated Akt2 phosphorylation and determined the effects on Akt substrates and glucose uptake. We incubated isolated epitrochlearis muscles from 9-month-old AL and CR (~60-65% of AL intake for 6months) rats with or without MK-2206 and measured insulin-stimulated (1.2nM) glucose uptake and phosphorylation of the insulin receptor (Tyr1162/1163), pan-Akt (Thr308 and Ser473), Akt2 (Thr308 and Ser473), AS160/TBC1D4 (Thr642), and Filamin C (Ser2213). Incubation of isolated skeletal muscles with a dose of a selective Akt inhibitor that eliminated the CR-induced increases in Akt2 phosphorylation prevented CR's effects on insulin-stimulated glucose uptake, pAS160 Thr642 and pFilamin C Ser2213 without altering pIR Tyr1162/1163. These data provide compelling new evidence linking the CR-induced increase in insulin-stimulated Akt2 phosphorylation to CR's effects on insulin-mediated phosphorylation of Akt substrates and glucose uptake in skeletal muscle.
AB - Calorie restriction (CR; ~60% of ad libitum, AL, consumption) improves insulin-stimulated glucose uptake in skeletal muscle. The precise cellular mechanism for this healthful outcome is unknown, but it is accompanied by enhanced insulin-stimulated activation of Akt. Previous research using Akt2-null mice demonstrated that Akt2 is essential for the full CR-effect on insulin-stimulated glucose uptake by muscle. However, because Akt2-null mice were completely deficient in Akt2 in every cell throughout life, it would be valuable to assess the efficacy of transient, muscle-specific Akt inhibition for attenuation of CR-effects on glucose uptake. Accordingly, we used a selective Akt inhibitor (MK-2206) to eliminate the CR-induced elevation in insulin-stimulated Akt2 phosphorylation and determined the effects on Akt substrates and glucose uptake. We incubated isolated epitrochlearis muscles from 9-month-old AL and CR (~60-65% of AL intake for 6months) rats with or without MK-2206 and measured insulin-stimulated (1.2nM) glucose uptake and phosphorylation of the insulin receptor (Tyr1162/1163), pan-Akt (Thr308 and Ser473), Akt2 (Thr308 and Ser473), AS160/TBC1D4 (Thr642), and Filamin C (Ser2213). Incubation of isolated skeletal muscles with a dose of a selective Akt inhibitor that eliminated the CR-induced increases in Akt2 phosphorylation prevented CR's effects on insulin-stimulated glucose uptake, pAS160 Thr642 and pFilamin C Ser2213 without altering pIR Tyr1162/1163. These data provide compelling new evidence linking the CR-induced increase in insulin-stimulated Akt2 phosphorylation to CR's effects on insulin-mediated phosphorylation of Akt substrates and glucose uptake in skeletal muscle.
KW - Caloric restriction
KW - GLUT4
KW - Glucose transport
KW - Insulin resistance
KW - Insulin sensitivity
UR - http://www.scopus.com/inward/record.url?scp=84865077987&partnerID=8YFLogxK
U2 - 10.1016/j.bbadis.2012.07.012
DO - 10.1016/j.bbadis.2012.07.012
M3 - Article
C2 - 22846604
AN - SCOPUS:84865077987
VL - 1822
SP - 1735
EP - 1740
JO - Biochimica et Biophysica Acta - Molecular Basis of Disease
JF - Biochimica et Biophysica Acta - Molecular Basis of Disease
SN - 0925-4439
IS - 11
ER -